Synthetic peptides bind to high-affinity thrombin receptors and modulate thrombin mitogenesis

Pept Res. Nov-Dec 1988;1(2):65-73.

Abstract

Initiation of cell proliferation by thrombin requires signals generated by thrombin interaction with specific high-affinity receptors and thrombin enzymic activity. Using synthetic peptides representing various domains of thrombin, we have identified a region adjacent to the proteolytic pocket of thrombin which confers high-affinity binding and generation of mitogenic signals. One peptide, representing residues 508 to 530 of human prothrombin (p508-530), inhibits up to 70% of the specific binding of 125I-alpha-thrombin at concentrations of less than 100 nM, enhances the ability of thrombin to stimulate DNA synthesis and stimulates DNA synthesis in cells treated with 25 ng/ml phorbol myristate acetate (PMA). Thus, this peptide or a portion of this peptide appears to represent the high-affinity receptor binding domain of thrombin. In contrast to the 23 amino acid peptide (p508-530), the tetrapeptide RGDA (p517-520) contained in this region competes for 125I-thrombin binding at concentrations from 100 to 2000 nM, but inhibits rather than stimulates the mitogenic effects of alpha-thrombin. Non-homologous peptides, or fibronectin-specific peptides (such as RGDS or GRGDSP) do not compete for 125I-alpha-thrombin binding and have no effect on thrombin mitogenesis. These studies demonstrate that peptides representing portions of the binding domain of thrombin: i) can generate receptor-occupancy related signals that enhance thrombin mitogenesis and are themselves mitogenic in cells treated with PMA; or ii) in the case of RGDA (which may be too small to generate signals), can act as antagonists, inhibiting the mitogenic effects of thrombin by preventing thrombin-receptor interaction.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Amino Acid Sequence
  • Animals
  • Binding, Competitive
  • Cell Division / drug effects*
  • Fibroblasts / drug effects*
  • Fibronectins / metabolism
  • Humans
  • Mice
  • Models, Molecular
  • Molecular Sequence Data
  • Oligopeptides / metabolism
  • Peptide Fragments / metabolism*
  • Peptide Fragments / pharmacology
  • Protein Conformation
  • Prothrombin / metabolism*
  • Prothrombin / pharmacology
  • Receptors, Cell Surface / metabolism*
  • Receptors, Thrombin
  • Sequence Homology, Nucleic Acid
  • Tetradecanoylphorbol Acetate / pharmacology

Substances

  • Fibronectins
  • Oligopeptides
  • Peptide Fragments
  • Receptors, Cell Surface
  • Receptors, Thrombin
  • Prothrombin
  • glycyl-arginyl-glycyl-aspartyl-seryl-proline
  • arginyl-glycyl-aspartyl-alanine
  • arginyl-glycyl-aspartyl-serine
  • Tetradecanoylphorbol Acetate